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Engineers have built a robot designed to emulate sperm cells which they can then control with magnets, called MagnetoSperm.

The artificial design has a body about six times the length of human sperm and is a metal-coated head. Using a magnetic field roughly equivalent to a fridge magnet the engineers managed to make the robot "swim" forward and steered it towards a fixed point. The team hope their findings will have useful applications in both medicine and manufacturing.

"We have built a biological inspired micro-robot that looks like a sperm cell but is completely fabricated in the lab," University of Twente robotics engineer Dr. Sathak Misra said.

Previous studies of the whip-like flagellum, used by sperm cells to propel themselves, have included attaching magnetic tails to red blood cells and guiding real sperm cells into metal microtubes.

The new invention is made from a strong, flexible polymer with a metal layer painted to its head with a technique called electron beam evaporation.

"The magnetic head is used to orient it in a certain direction and then, just by flapping its tail, it starts to move forward," Misra adds. "The flapping happens because we change the current in the coils."

Misra and his colleagues showed they could steer the robot with a degree of precision by adjusting magnetic field changes with a computer.